Synthesis of 1-methyl-, 4-nitro-, 4-amino-and 4-iodo-1,2-dihydro-3<i>H</i>-pyrazol-3-ones
作者:Y. C. Fiamegos、G. A. Pilidis、G. Varvounis
DOI:10.1002/jhet.5570380509
日期:2001.9
4-Aminopyrazole-3-ones 4b, e, f were prepared from pyrazole-3-ones 1b-d in a four-step reaction sequence. Reaction of the latter with methyl p-toluenesulfonate gave 1-methylpyrazol-3-ones 2b-d. Compounds 2b-d were treated with aqueous nitric acid to give 4-nitropyrazol-3-ones 3b-d. Reduction of compounds 3b-d by catalytic hydrogenation with Pd-C afforded the 4-amino compounds 4b, e, f. Using similar